Create a bookmark with the following string as the URL:

Code:
javascript:(function(){var%20ca,cea,cs,df,dfe,i,j,x,y;function%20n(i,what){return%20i+%22%20%22+what+((i==1)?%22%22:%22s%22)}ca=cea=cs=0;df=document.forms;for(i=0;i<df.length;++i){x=df[i];dfe=x.elements;if(x.onsubmit){x.onsubmit=%22%22;++cs;}if(x.attributes[%22autocomplete%22]){x.attributes[%22autocomplete%22].value=%22on%22;++ca;}for(j=0;j<dfe.length;++j){y=dfe[j];if(y.attributes[%22autocomplete%22]){y.attributes[%22autocomplete%22].value=%22on%22;++cea;}}}alert(%22Removed%20autocomplete=off%20from%20%22+n(ca,%22form%22)+%22%20and%20from%20%22+n(cea,%22form%20element%22)+%22,%20and%20removed%20onsubmit%20from%20%22+n(cs,%22form%22)+%22.%20After%20you%20type%20your%20password%20and%20submit%20the%20form,%20the%20browser%20will%20offer%20to%20remember%20your%20password.%22)})();


Then if you click that bookmark on a site that doesn't allow password saving it'll disable that code. You might have to click it again when visiting the site next to allow the loading of your saved password. You can get GreaseMonkey to do the same thing automatically, if it is too much of a problem.

Pioneer PDP-5020FD, Marantz SR6011
Axiom M5HP, VP160HP, QS8
Sony PS4, surround backs
-Chris